1. Field of the Invention
The present invention relates to a forced draft direct vent type room heater which forcibly supplies air for combustion and exhausts a combusted gas.
2. Description of the Related Art
Conventionally, such a room heater is known as is described in Japanese Patent No. 4050744. This room heater has a burner housed in a combustion housing provided in an outer case. In the combustion housing, air for combustion is supplied and a combusted gas is exhausted by a combustion fan. In an exhaust path for exhausting the combusted gas therethrough, a main heat exchanger is provided in the upstream side, and a supplementary heat exchanger is provided in the downstream side. In the outer case, an air intake and a vent hole are provided. In the outer case, a warm air fan is provided, and this warm air fan takes in room air from the air intake and sends the air to the inside of the room from the vent hole through the main heat exchanger and the supplementary heat exchanger.
The room heater also has the vent hole opened in the lower part of the front panel of the outer case, and leads the room air (warm air) having passed through the section in which the main heat exchanger is arranged to the vent hole through a space in the lower part of the combustion housing.
In addition, in such a room heater, the one is also known that has a drain dish arranged in the lower space of the combustion housing, and makes a drain (condensation water) formed in an exhaust extension tube (tube for exhausting exhaust gas to outside) which is connected to a downstream end of the exhaust path, to flow into the drain dish. In the above one, the drain which flowed into the drain dish is heated by a warm air flowing in the lower space of the combustion housing to be evaporated.
Here, in a weak combustion period, the temperature of the combusted gas flowing in the exhaust extension tube is lowered, and the amount of a formed drain increases, but the temperature of the warm air is lowered, so that an amount of an evaporated drain from the drain dish decreases. Accordingly, when the weak combustion is continued, the drain overflows from the drain dish. In order to prevent the overflow of the drain from the drain dish, it is necessary to shorten the length of the exhaust extension tube and to reduce the amount of the formed drain. As a result, a position where the room heater can be set becomes limited.